Really. If there weren't cameras, we wouldn't have movies, television, tabloids, or slideshows. And really, what good is a family get together if you can't bore everyone with your slideshows from your last 15 vacations?
But seriously, a camera is a box. You got film on the one side, you got an image-forming optic on the other.
Nothing too fancy.
Except that film comes in many many many flavours. There's sheet film, roll film, cassette film, pack film, and although it's not technically film, there's also plates, which are a lot like film, but older, thicker, heavier, and more painful to work with.
The image optics... there's lenses, pinholes.. well, there's lenses and pinholes.
And of course, to protect the film, there's a shutter.
And to control how much light is coming through, and also depth of field, there's an iris (aperture).
But of course, the best definition is "A lightproof box that lets light in".
I have two cameras that I usueally use, and a handful that I don't.
Nikon makes nice cameras. Well, they used to. Now, they make nasty cameras. They still make nice lenses, but it's hard to get a NEW Nikon that a "real camera" person would be happy with. The FM2n is about as close as it comes. While other companies are making knockoff K1000's, Nikon actually refined the old designs. The FM2n has a fixed finder, TTL center weighted meter, DOF preview, multiple in-register exposures, will take a motor drive, has a PC connection and a hot shoe, and will X sync at 1/250, with a top shutter speed of 1/4000. It takes 35mm film cassettes.
I looked at the autofocus bodies and said "no". The FM2n is one of the few cameras that is COMPLETELY mechanical, with the exception of the meter. If the batteries die, no big deal... just eyeball meter (sunny 16, 11, etc). On an N50, most everything dies with the battery. That's absolutely useless.
I also have a YashicaMat LM for snapshots. It has a nice, slow lens (f/3.5), but will X sync anywhere from 1 to 1/500. The shutter speeds are a little wierd on this camera, but that's no big deal. It's a great snapshot camera. That's what I got it for, that's what I use it for. If I wanted a "REAL" TLR, I'd either get a Mamiya or a Yashica 124G.
Can't forget this one, the first real camera I ever had. A Yashica Electro 35 GSN. Aperture Priority autoexposure, fixed lens rangefinder. Not too bad. I've taken nice pictures with it. 45mm f/1.7 Yashinon lens. I usually use it now for long exposure stuff, because of the fast lens. f/1.7 and be there.